There has been known a glass panel unit in which two or more glass panels are stacked with one or more gaps in-between to form one or more hermetically enclosed spaces, and the spaces are made to be in a vacuum state. This type of glass panel unit is also referred to as a multiple glass panel. This glass panel unit has high thermal insulating properties. It is important that the glass panel unit keeps the vacuum state.
There has been proposed use of a getter to maintain the vacuum state of the glass panel unit. The getter is a substance capable of adsorbing gas. For example, JP 2013-514245 A (WO 2011/072646 A1) discloses techniques of using stacked glass plates with different sizes and providing the getter on a periphery of one glass plate which is not covered with the other. However, according to the techniques of the document, the getter protrudes laterally, and this may lead to a poor appearance and a decrease in handleability.